How does it happen?
Auburn needs to win out. This includes winning at Ole Miss to get to 10-1, 6-1 in the league. Given the remaining schedules of all involved teams, this is by far the most difficult thing that needs to occur as Auburn also plays at Georgia and has games against South Carolina and Texas A&M.
Ole Miss needs to win all of its remaining games except the Auburn game. This gives the Rebels a record of 10-1, 6-1. And it loses the head to head tiebreaker with Auburn. Keep that in mind as we'll come back to it.
Alabama also needs to win out. This includes beating Mississippi St. You can probably see where this is going. The Crimson Tide would have a record of 10-1, 6-1. And it would own the head to head tiebreaker with Mississippi St. but would lose it to Ole Miss.
Finally, Mississippi St. needs to win out except for the Alabama game. The record would be the same 10-1, 6-1 record that the others all have. And the tiebreak situation would be similar.
If all of this occurs, we would have the following standings going into the final day of the regular season:
Auburn (10-1, 6-1) - Win tiebreaker vs Ole Miss, lose vs Mississippi St.
Alabama (10-1, 6-1) - Win tiebreaker vs Mississippi St., lose vs Ole Miss
Ole Miss (10-1, 6-1) - Win tiebreaker vs Alabama, lose vs Auburn
Mississippi St. (10-1, 6-1) - Win tiebreaker vs Auburn, lose vs Alabama
And we would have the following games:
Mississippi St. at Ole Miss
Auburn at Alabama
For the sake of this exercise, let's assume the Iron Bowl is the 3:30 ET game on CBS. The loser is eliminated from contention. Whoever the winner is eliminates one of the Mississippi teams, but then needs that team to win the Egg Bowl that night to win the West or it would lose the tiebreaker. Fun times and chaos to root for.
As a final side note, if there is some sort of three way tie at 7-1, both Mississippi schools are probably screwed given the final tiebreaker is conference record of non-division opponents and both played Vanderbilt.